Apparatus and method for electrically contacting wafer in electronic chemical plating cell

ABSTRACT

An apparatus and method for electrically contacting a wafer in an electronic chemical plating cell includes a plating bath containing an electrolytic solution therein, an anode member arranged at a lower portion in the plating bath, a support member for arranging a wafer at an upper portion in the plating bath to face the anode member, a first cathode contact member electrically contacting an edge of the wafer, a second cathode contact member electrically contacting the center of the wafer, and a power supply electrically connected among the anode member, the first cathode contact member and the second cathode contact member to supply the power. Since resistance of a seed layer is reduced, it is possible to improve uniformity of the plating layer.

This application claims the benefit of the Korean Patent Application No.P2005-85107, filed on Sept. 13, 2005, which is hereby incorporated byreference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a semiconductor device, and moreparticularly, to an apparatus and method for electrically contacting awafer in an electronic chemical plating cell.

2. Discussion of the Related Art

Generally, in a process of manufacturing a semiconductor device, anelectronic chemical plating method using an electronic chemical platingcell is used as a method for forming a metal layer on a wafer.

FIG. 1 is a perspective view illustrating a related art electronicchemical plating cell.

Referring to FIG. 1, the related art electronic chemical plating cellincludes a container 10. The container 10 is opened at the top toreceive and support a wafer holder 12. Preferably, the container 10 ismade of an annular cell of an electrical insulating material such asplastic, flexible glass (acryl product), LEXAN, PVC, CPVC, and PVDF.

The wafer holder 12 is used as a top cover of the container 10. Thecontainer 10 is generally formed to correspond to the shape and size ofthe wafer W. An inlet (not shown) is provided on the bottom of thecontainer 10 so that an electron plating solution is supplied thereinto.The electron plating solution is supplied to the container 10 by a pump(not shown) connected with the inlet. Thus, the electron platingsolution is in contact with a surface of the wafer W.

A cathode contact member 14 is arranged on a bottom surface of the waferholder 12. For electron plating, the cathode contact member 14 suppliesa current to the surface of the wafer W.

The cathode contact member 14, as shown in FIG. 2, includes a main body14 a, and contact strips 14 b (or contact pins) extended from the mainbody 14 a and contacting the wafer W. The cathode contact member 14transfers electric energy supplied from an external power supply (notshown) to the wafer W. The contact pins 14 b are in contact with theedge of the wafer W.

The container 10 further includes a chamber 18. The chamber 18 isprovided with a consuming anode 16 for supplying a metal supply.Although not shown, the consuming anode 16 is made of a metal partcovered with a porous cover, such as pure copper, a metal wire, a boringmetal sheet or a solidified metal sheet. The consuming anode 16 iselectrically connected with the power supply.

The contact pins 14 b of the cathode contact member 14 are each formedwith the same extension length L. Portions marked by black color at theends of the contact pins 14 b are in contact with the wafer W. Thecontact portion between the wafer W and the cathode contact member 14 ismaintained in a region within the range of 2mm from the edge of thewafer W.

A related art apparatus and method for electrically contacting a waferin an electronic chemical plating cell will now be described withreference to FIG. 3. For convenience of description, the container 10and the chamber 18 shown in FIG. 1 are referred to as a plating bath 300that is an external container of an electron chemical plating cell.

The related art apparatus for electrically contacting a wafer in anelectronic chemical plating cell, as shown in FIG. 3, includes a platingbath 300 containing an electrolytic solution, a consuming anode 16arranged at a lower portion in the plating bath 300, a wafer W arrangedat an upper portion in the plating bath 300 to face the consuming anode16, a cathode contact member 14 electrically contacting the edge of theplating surface of the wafer W along the corner of the wafer W, and apower supply 310 electrically connected between the consuming anode 16and the cathode contact member 14 to supply the power. A metal seedlayer (not shown) is formed on the plating surface of the wafer W.

Various factors affect the uniformity of the plating layer during anelectronic chemical plating process. Examples of the factors include aresistance R_(bath) of the electrolytic solution, the distanceD_(plating) between the wafer W and the consuming anode 16, a resistanceR_(seed) of the metal seed layer, thickness of the metal seed layer, theuniformity of the seed layer, and the type of electric contact betweenthe wafer W and the cathode contact member 14, which can be either a“wet” contact or a “dry” contact. “Wet” contact refers to the exposureof the contact portion between the wafer W and the cathode contactmember 14 to the electrolytic solution as shown in FIG. 4. “Dry” contactrefers to the sealing of the contact portion between the wafer W and thecathode contact member 14 using a bag member 41 so as not to expose thecontact portion to the electrolytic solution, as shown in FIG. 5.

To obtain optimized uniformity required for the electronic chemicalplating process with regard to the aforementioned factors, factorsincluding high resistance R_(bath) of the electrolytic solution, theoptimized distance D_(plating), low resistance R_(seed) of the metalseed layer, thick seed layer and uniformity of the seed layer arerequired. Among the factors, the factors relating to the seed layer havebeen studied. However, many studies of the other factors are stillrequired.

SUMMARY

Consistent with the present invention there is provided an apparatus andmethod for electrically contacting a wafer in an electronic chemicalplating cell, which may substantially obviate one or more problems dueto limitations and disadvantages of the related art.

Consistent with the present invention, there is provided an apparatusand method for electrically contacting a wafer in an electronic chemicalplating cell, in which uniformity of a metal layer plated on a wafer maybe optimized during an electronic chemical plating process.

Consistent with the invention, as embodied and broadly described herein,there is further provided an apparatus for electrically contacting awafer in an electronic chemical plating cell includes a plating bathcontaining an electrolytic solution therein, an anode member arranged ata lower portion in the plating bath, a support member for arranging awafer at an upper portion in the plating bath to face the- anode member,a first cathode contact member electrically contacting an edge of thewafer, a second cathode contact member electrically contacting thecenter of the wafer, and a power supply electrically connected to theanode member, the first cathode contact member and the second cathodecontact member to supply the power.

The first cathode contact member is provided with a plurality of contactpins contacting the edge of the wafer several times along the corner ofthe wafer.

In another aspect consistent with the present invention, a method forelectrically contacting a wafer in an electronic chemical plating cellincludes preparing a plating bath containing an electrolytic solution,arranging an anode member at a lower portion in the plating bath,arranging a wafer at an upper portion in the plating bath to face theanode member, arranging a first cathode contact member to electricallycontact an edge of the wafer, arranging a second cathode contact memberto electrically contact the center of the wafer, and connecting a powersource to the anode member, the first cathode contact member and thesecond cathode contact member to supply the power source.

The first cathode contact member contacts the edge of the wafer severaltimes along the corner of the wafer, and the second cathode contactmember contacts the center of the wafer one time or more.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation consistent with the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments consistent with theinvention and together with the description serve to explain theprinciple of the invention. In the drawings:

FIG. 1 is a perspective view illustrating a related art electronicchemical plating cell;

FIG. 2 illustrates a cathode contact member of FIG. 1;

FIG. 3 illustrates an electrical contact structure of FIG. 1;

FIG. 4 illustrates a “wet” contact;

FIG. 5 illustrates a “dry” contact; and

FIG. 6 illustrates an apparatus and method for electrically contacting awafer in an electronic chemical plating cell consistent with the presentinvention.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodimentsconsistent with the present invention, examples of which are illustratedin the accompanying drawings. Wherever possible, the same referencenumbers will be used throughout the drawings to refer to the same orlike parts.

An apparatus and method for electrically contacting a wafer in anelectronic chemical plating cell consistent with the present inventionwill be described with reference to FIG. 6.

FIG. 6 illustrates an apparatus and method for electrically contacting awafer in an electronic chemical plating cell according to the presentinvention.

As shown in FIG. 6, the apparatus for electrically contacting a wafer inan electronic chemical plating cell includes a plating bath 600 having acontainer (not shown) and a chamber (not shown) to contain anelectrolytic solution therein, an anode member 610 of copper arranged inthe chamber provided at a lower portion in the plating bath 600, a waferholder (not shown) serving as a support member for arranging a wafer Win the container provided at an upper portion in the plating bath 600 toface the anode member 610, a first cathode contact member 620electrically contacting the edge of the wafer W, a second cathodecontact member 630 electrically contacting the center of the wafer W,and a power supply 640 electrically connected to the anode member 610,the first cathode contact member 620 and the second cathode contactmember 630 to supply the power.

Although not shown, the wafer holder may be comprised of the samestructure as that of the wafer holder 12 shown in FIG. 1. The firstcathode contact member 620 is provided with a plurality of contact pins,similar to contact pins 14 b shown in FIG. 2, contacting the edge of thewafer W several times along the corner of the wafer W. The contact pinsare formed at constant intervals. The first cathode contact member 620has the same structure as that of the cathode contact member 14 shown inFIG. 2.

As described above with reference to FIG. 6, the method for electricallycontacting a wafer in an electronic chemical plating cell consistentwith the present invention is as follows.

The plating bath 600 containing the electrolytic solution is prepared.The anode member 610 is arranged at the lower portion in the platingbath 600. The wafer W is arranged at the upper portion in the platingbath 600 to face the anode member 610. The first cathode contact member620 electrically contacts the edge of the wafer W, and the secondcathode contact member 630 electrically contacts the center of the waferW. The power is supplied to the anode member 610, the first cathodecontact member 620 and the second cathode contact member 630.

The first cathode contact member 620 contacts the edge of the wafer Wseveral times along the corner of the wafer W. The second cathodecontact member 630 contacts the center of the wafer W one time or more.

As described above, in the apparatus and method for electricallycontacting a wafer in an electronic chemical plating cell according tothe present invention, since resistance R_(seed) of the seed layer isreduced, it is possible to improve uniformity of the plating layer.Also, in cases where a large-sized wafer having, for example, athickness of 300 mm or greater, is used, it is possible to remarkablyimprove the uniformity of the plating layer.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. An apparatus for electrically contacting a wafer in an electronicchemical plating cell comprising: a plating bath having an electrolyticsolution therein; an anode member arranged in a lower portion of theplating bath; a support member for arranging a wafer in an upper portionof the plating bath to face the anode member; a first cathode contactmember electrically contacting an edge of the wafer; a second cathodecontact member electrically contacting the center of the wafer; and apower supply electrically connected to the anode member, the firstcathode contact member and the second cathode contact member.
 2. Theapparatus of claim 1, wherein the first cathode contact member isprovided with a plurality of contact pins contacting the edge of thewafer along the corner of the wafer.
 3. The apparatus of claim 2,wherein the contact pins are formed at constant intervals.
 4. A methodfor electrically contacting a wafer in an electronic chemical platingcell comprising: preparing a plating bath containing an electrolyticsolution; arranging an anode member in a lower portion of the platingbath; arranging a wafer in an upper portion of the plating bath to facethe anode member; arranging a first cathode contact member toelectrically contact an edge of the wafer; arranging a second cathodecontact member to electrically contact the center of the wafer; andsupplying electrical power from a power source connected to the anodemember, the first cathode contact member and the second cathode contactmember.
 5. The method of claim 4, wherein arranging the first cathodecontact member comprises arranging the first cathode contact member incontact with the edge of the wafer at a plurality of points along thecorner of the wafer.
 6. The method of claim 4, wherein arranging thesecond cathode contact member comprises arranging the second cathodecontact member to contact the center of the wafer at a plurality ofpoints.
 7. The method as claimed in claim 4, wherein the wafer has athickness of 300 mn or greater.